Knife structure for trimming mechanism



March 16, 1937. J/BRUSSELL 2,073,920

KNIFE STRUCTURE FOR TRIMMiNG MECHANISMS Filed Sept. 5, 1936 INVENTOR.

7 JACO BRUSSELL BY Patented Mar. 16, 1937 UNITED STATES PATENT ()FFICE- KNIFE STRUCTURE FOR TRINIMING MECH- ANIS Jacob Brussell, New York, N. Y. Application September 5, 1936, Serial No. 99,521

11 Claims.

In application Ser. No.-65,802, filed February 21, 1936, now Reissue Patent No. 20,204, dated December 15, 1936, I have described and claimed a special arrangement of the mechanisms whereby a more'eflective action-is obtained. One of the features of said application is the provision of spring meanswhereby on the downward stroke of the knife the pressure is increased while on the upward stroke the pressure is decreased, thereby greatly lengthening the useful life of the knife.

Because of the high speed at which commercial sewing machines operate, say at 3,500 to 4,000 R. P. M., it is highly desirable to provide a lubricating means for the knife in view of the reciprocation thereof under a relatively high pressure due to the spring action which causes considerable friction between the knife and ledger b ade. 1

In order to obtain the desired and effective lubrication of the knife, I provide, usually 5 in both of the surfaces thereof which contact with the ledger blade, an opening through which a lubricant may be introduced so as to flow over the contact faces of the knife and thus lubricate the same. 0 lubrication be the minimum necessary forthe purpose, and care must be taken that oil or the like does not come in contact with the fabric being trimmed. Since the knife is ordinarily reversible, I gen- 5 erally provide the same with a series of openings, so that lubricant may be supplied from either the top or the bottom of the knife, whichever side is in use. To accomplish this, there are provided at least two transverse openings passing from 40 side to side of the knife or, in other words, from one face to the other. Extending vertically from the top and bottom of the knife are additional openings'which communicate with the transverse openings. Lubricant is introduced into the ver- 45 tical opening which happens to be at the top and it flows therefrom into-the transverse opening-and thus onto the faces of the knife.

In order to insure uniform lubricationof each of the faces, I generally provide a groove which 50 is in a substantially vertical position allowing the lubricant to be distributed over the contact face of the knife. Where two transverse openings are provided, the groove connects with both of them and furthermore, the end of the groove is below 55 the lower-most opening. This insures that lubri- It is desirable that the amount of cant coming in through the top opening will not flow out of the lower opening since it tends to accumulate in that portion of the groove which is below said lower opening.

I may provide means for preventing the lubri- 5 cant from flowing too rapidly through the system of openings by introducing cotton waste or the like into said openings, thereby holding the lubricant within the same and allowing the said lubricant to feed at a slow rate. 1 In the accompanying drawing constituting a part hereof and in which like reference characters indicate like parts.

Figure 1 is a side elevational view of a pinking mechanism embodying the present invention. 5

Figure 2 is a perspective view of the knife, and Figure 3 is a longitudinal cross-sectional view thereof taken along the line 3-3 of Fig. 2.

The device comprises a base I which is attached to the base or bed of a sewing machine-and secured in a threaded portion thereof by means of screw 2. At the rear of base I is a lug 3 to which is pivoted the rear end of a lever arm 4 by means of pin 5, an upstanding boss 6 at an intermediate portion of the lever has a pivoted rod I which is normally connected to the rotating mechanism of a sewing machine, whereby the arm 4 is reciprocated. The front portion 8 of said arm has a pivot 9 in which is held a fork l0 provided with a screw II at the free end thereof.

The knife consists of two V-shaped blades l2 and I3 arranged back to back and connected by a portion l4 which is usually integral with the two blades. A transverse opening l6 provides means whereby the knife may be held in the fork III by screw ll passing through said opening.

Each of the knives has grooves l6 and H on the contact faces thereof. These grooves are in a substantially vertical position and they are placed near the rear of each of the contact faces. A pair 40 of transverse openings l8 and I9 passing from face to face of each blade communicate with grooves I6 and I1. As shown more particularly in Figure 3, the openings l8 and I 9 enter the grooves at points removed from the ends of said grooves. Vertical openings 2| and 22 from the top and 'bottom ends of each blade communicate with openings l8 and I9, respectively. The openings 2| and 22 maybe filled cotton waste or the like.

A spring 23 has follower 24 which bears against the blade l3 of the knife and the opposite end of said spring is secured to the arm 4 by screw 25.

A member 2615 provided with a cap 21, upon the rotation of which the pressure of the spring and itsfollower may be varied at will. The knife operates within a ledger blade 28 and the adjustment of spring 23 gives the desired contact pressure between the knife and ledger blade.

In operation at high speed it is essential that is adequate lubrication of the contact faces of the knife and ledger blade be had. At the same time it is necessary thatno oil come in contact with the fabric being operated upon. Therefore, the grooves l6 and I! are placed at the rear of the 10 contact faces, so that, when oil -is introduced through opening 2| for example, it flows through 'opening l8 and into grooves l6 and I1 thus lubrieating the face of the knife. However, since the pinked portion of the fabric does not extend as far back as grooves l6 and I1 there will be no .direct contact between the fabric and the oil,

thus avoiding soiling of the fabric.

The lower endsof the grooves being below opening l9 will not allow any substantial amount .of oil to enter into opening l9 and thus avoids undue waste of oil. By introducing suitable packing material into the lubricating system it will also tend to avoid loss of oil, and it will prevent soiling of the fabric being trimmed.

The knife disclosed herein is a four way knife which may be reversed to use edges on all four corners thereof. The lubricating system has been constructed in its present form to take care of the necessary reversals of such a knife. However,

my invention is equally applicable to a knife having a lesser number of cutting edges and it may be applied to a knife having a single cutting edge as well. In such a case the lubricating system is, of course, greatly simplified.

Although I have described my invention giving one specific embodiment thereof it will be apparent to those skilled in the art that various changes and modifications in the physical structure and in the materials used may be made without departing from the principles set forth herein. A greater or lesser number of grooves may be made and the angle thereof may be different from that shown. The several openings may be placed as desired and in some cases may be dispensed with.

These and other changes may be made within the spirit of my invention which .is to be broadly construed and not to be limited except by the claims attached hereto.

What I claim is:-

1. In a trimming mechanism for sewing machines, an arm, a reciprocating knife thereon, a ledger blade cooperating with said knife, means for applying pressure between said knife and blade, at least one opening at each of the contact faces of said knife and blade, and means for admitting lubricant to said opening.

2. In a trimming mechanism for sewing machines, an arm, a reciprocating knife thereon, a

ledger blade cooperating with said knife, means for applying pressure between said knife and blade, an opening at a contact face of said knife, and means for admitting lubricant to said opening.

3. In a trimming mechanism for sewing machines, an arm, a reciprocating knife thereon, a ledger blade cooperating with said knife, means for applying pressure between said knife and blade, a plurality of openings at a contact face of said knife, a groove connecting said openingson said face, and means for admitting lubricant to said openings and groove.

4. In a trimming mechanism for sewing machines, an arm, a reciprocating V-shaped knife thereon, a ledger blade cooperating with said knife and blade, an opening at a contact face of said knife, a groove on said face communicating with said opening and means for admitting lubricant to said opening.

5. A knife for a trimming mechanism comprising a. contact face having an opening therein and means for admitting lubricant to said opening.

6. A knife for trimming mechanism comprising a contact face having an opening therein, a groove on said face communicating with said opening and means for admitting lubricant to said opening.

'7. A V-shaped knife for a trimming mechanism comprising a pair of contact faces, said knife having an opening extending from face to face and means for admitting lubricant to said open- 8. A V-shaped knife for a trimming mechanism comprising a pair of contact faces, said knife having an opening extending from face to face, a groove on at least one of said faces communicating with said opening and means for admitting lubricant to said opening.

9-. A V-shaped knife for a trimming mechanism comprising a. pair of contact faces, said knife having an opening extending from face to face, an end of said knife being provided with an opening connecting with said first mentioned opening for admitting lubricant thereto.

10. A V-shaped knife for a trimming mechanism comprising a pair of contact faces, said knife having a pair of openings extending from face to face, the top and bottom of said knife each being provided with an opening connecting with one of said first mentioned openings for admitting lubricant thereto.

11. A knife for a trimming mechanism comprising a contact face having an opening therein, a groove on said face communicating with said opening, said groove being at the rear of said contact face and means for admitting lubricant to said opening.

JACOB BRUSSELL. 

